1. Field of the Invention
The field of the invention is Light Emitting Diode (LED) lamp packages, and more particularly, LED lamp packages for packaging an LED driver with a LED.
2. Description of the Related Art
LEDs are commonly used as status indicator lights and in numerical and alphanumerical displays.
FIG. 1 shows a cross-sectional view of a conventional LED lamp package for packaging an LED chip 105, on which an LED is fabricated. The LED chip 105 is typically placed in a reflector cavity 110 for reflecting light emitted from the sides of the LED chip 105 upwards. The LED package includes two contact leads 112,117, one of which is connected to the reflector cavity 110, and the other of which is connected to a top contact 120 on the LED chip 105 by a bond wire 125. The top portions of the leads 112,117 and the LED chip 105 are enclosed by a light transparent encapsulant 130. The encapsulant 130 is used to hold the leads 112,117 in place and to increase the light transmission out of the LED chip 105.
The LED in the LED lamp package is typically driven by an external LED driver. The LED driver drives a current to the LED according to the specifications of the LED and lighting requirements.
Embodiments of the present invention provide LED lamp packages for packaging an LED driver circuit with an LED.
An LED lamp package according to one embodiment includes a ground lead, an control input lead, and a voltage supply lead, wherein the ground lead includes a reflector dish. The LED lamp package further includes an LED driver chip comprising an LED driver circuit and an LED chip comprising an LED. Both the LED driver chip and the LED chip are mounted on the reflector dish of the ground lead. The voltage supply lead is connected to the LED driver chip by a first bond wire, the input lead is connected to the LED driver chip by a second bond wire, and the LED driver chip is connected to the LED chip by a third bond wire. The top portions of the leads are enclosed by a light transparent encapsulant.
In another embodiment, the control input lead is omitted. In this embodiment, the LED driver circuit on the LED driver chip is configured to automatically turn on when a sufficiently high voltage power supply is applied to the LED driver circuit.
In another embodiment, the LED chip is mounted on top of the LED driver chip in the LED lamp package. In this embodiment, the LED driver chip includes an attachment pad, on which the bottom surface of the LED chip is attached.
An advantage of the LED lamp packages according to the invention is that they allow a systems manufacturer to conveniently plug the LED lamp packages into systems for lighting applications without having to provide separate LED drivers to drive the LEDs in the LED lamp packages.
Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.
It to be understood that the components shown in the following figures are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the invention.
FIG. 1 shows a cross-sectional view of a conventional LED lamp package.
FIGS. 2A to 2C show three configurations for connecting an LED driver to an LED.
FIGS. 3A to 3C show the configurations of FIGS. 2A to 2C, respectively, in which the control input of the LED driver is omitted.
FIGS. 4A and 4B show a perspective view and a blown-up view of an LED lamp package according to an embodiment of the present invention.
FIGS. 5A and 5B show a perspective view and a blown-up view of a two-lead embodiment of the LED lamp package.
FIGS. 6A and 6B show a top view and a cross-sectional view of an LED lamp package according to another embodiment of the present invention, in which the LED chip is mounted on top of the LED driver chip.
FIG. 7 shows a detailed cross-sectional view of the LED chip mounted on top of the LED driver chip.
FIG. 8 shows a top view of another two-lead embodiment of the LED lamp package.